Study on mechanical properties of seawater sea-sand concrete columns confined with bamboo sheets

Monotonic axial compression tests were conducted on seawater sea-sand concrete columns confined with bamboo sheets (SSCCCBS) in this study. The effects of the number of bamboo sheet layers (NBSLs) (i.e., 1, 2, 3, 4, and 5 layers) and the angle of bamboo sheet reinforcement (ABSR) (i.e., 0° and 45°) on the mechanical properties of SSCCCBS were examined. Experimental results indicated that the failure mode of SSCCCBS specimens exhibited serrated cracks in the middle that extended longitudinally toward the ends. As NBSLs increased, the strength and ductility of SSCCCBS specimens showed significant improvement. The ultimate stress, ultimate stress increase ratio (\({f}_{cu}/{f}_{co}\)), ultimate strain increase ratio (\({\varepsilon }_{cu}/{\varepsilon }_{co}\)), and energy absorption rate of SSCCCBS specimens demonstrated an upward trend, with more pronounced increases in specimens with 0–3 layers of bamboo sheets and less pronounced increases in those with 3–5 layers. The current model was employed to predict the experimental outcomes and the results were compared with the test data. Based on the current model, improved models for ultimate stress, ultimate strain, and axial-lateral strain applicable to SSCCCBS were proposed, and the predicted results exhibited alignment with the experimental values.